The leptin receptor Ob-R expression (Panel A) and phosphorylation of the leptin receptor downstream signaling molecule STAT-3 (pSTAT3, Panel B) in cardiomyocytes freshly isolated from young (4-month-old) or aging (12-month-old) lean (C57) and <i>ob/ob</i> mice treated with or without leptin (1.0 and 50 nM) for 4 hrs.

<p>Protein expression of Ob-R and pSTAT-3 was normalized to the loading control GAPDH or total STAT-3, respectively. Insets: Representative gel blots of Ob-R, pSTAT-3 and STAT-3 proteins using specific antibodies. Mean ± SEM, n = 3 – 6 isolations, * p<0.05 <i>vs.</i> respective C57 group, # p<0.05 <i>vs.</i> respective <i>ob/ob</i> group.